1. Field of the Invention
The present invention relates to buoyant reflective materials that float on water when thrown; and, more particularly, to an abrasion resistant omnidirectionally reflective rope that reflects light back to the lighting source, and which can be thrown in the water towards a swimmer in distress from a vessel, or mark buoys or lobster traps, to increase visibility of the swimmer and buoys in the water and provide a margin of safety that reduces boating accidents during navigation in harbors under dimly lit conditions.
2. Description of the Prior Art
Boats and vessels for marine and lake use face special problems during dusk and nighttime navigation, or during fog events that limit visibility. Larger vessels and boats rely on board lighting sources to guide their way. Even then, marine craft risk collision with buoys attached to lobster traps or fishing nets. These collisions can damage smaller boats and lead to injury or loss of lives. In light of their large driving power and weight, navigation of marine craft requires precise control of a vessels speed and direction. As such, the navigator needs adequate visible clues to assess collision probabilities. Oftentimes, these visual clues are not available due to the limited range and area coverage provided by on board lighting sources.
When a swimmer is overboard, a floatation device is generally thrown and its location with respect to the swimmer is difficult to see in dimly illuminated conditions. It is also difficult to see when the swimmer in distress was able to reach the floatation device and is securely attached and can be hauled into the vessel by using a rope attached to the floatation device.
Retro-reflective reflectors are known in the art, but have not been available on rope that can be twisted and handled in a marine environment. Rope has been equipped with active powered lighting sources. Such rope is unsuited for marine craft applications due to the requirement of electrical power, which may be easily short circuited by sea water, or even lake water. In general, use of wires, bulbs, LEDS, photo-luminescent devices and other illumination sources presents extremely unreliable lighting sources, considering the abuse to which ropes are subjected in a marine craft environment. None of the prior art patents disclose an abrasion resistant omnidirectionally reflective rope suited for marine applications.
U.S. Pat. Nos. 6,394,623, 6,604,841, 6,907,685, 6,953,262 and 6,965,205, patent applications 20030206419, 20040037080, 20050162850 and 20060021585 disclose ropes with active illuminating devices such as a lamps, LEDs or electroluminescent devices that are powered by an electrical power source. These illuminated ropes do not omnidirectionally reflect light back to the source to thereby provide enhanced visibility during dusk, fog or dark surroundings. Moreover, electrical circuits used in these devices would likely be short circuited in a marine craft environment.
Numerous patents disclose reflective materials. Some of these patents disclose reflective elements having corner cube shapes embedded in rigid or flexible polymeric strips and monolayers of spherical beads, i.e. primarily glass beads bonded to a reflective sheet.
U.S. Pat. No. 3,176,584 to DeVries, et al. discloses that a reinforcing layer may be incorporated into an embedded lens retroreflective sheeting. The reinforcing layer may have a composition similar to that of the binder in which the microspheres are embedded. The layer may be applied to the back side of the secularly reflective layer via spraying, i.e., by a solvent-coating technique. Examples of the reinforcing layer materials disclosed include methyl methacrylate, flexible epoxy resins, chloro-sulfonated polyethylene, polystyrene, polypropylene, polycarbonate resin, ethyl cellulose, and cellulose acetate-butyrate. The reflective layer is typically very thin and fragile, i.e. in the order of 0.06 microns thick, and must be disposed in special relationship to the microspheres in order for the sheeting to provide useful retro-reflection. This thin fragile retro-reflection coating is unsuited for use as a rope that must withstand bending and twisting forces prevalent with marine craft applications.
U.S. Pat. No. 3,190,178 to McKenzie discloses reflex reflective sheeting. A monolayer of microspheres is embedded in a polymer to reflect the incoming light beam in the same direction as the incident beam. Since the sheet is formed by melting of the polymeric binder, it is rigid and therefore unsuitable for flexible ropes.
U.S. Pat. No. 4,025,159 to McGrath discloses cellular retroreflective sheeting. The cellular retroreflective sheeting comprises a base layer of retroreflective elements and a transparent cover film supported in spaced relation away from the base layer by a network of narrow intersecting bonds. These bonds form hermetically sealed cells within which retroreflective elements are isolated from retroreflective elements of different cells. The resultant sheeting achieves greater durability through use of bonds that are cured in situ after they have been thermoformed into sealing contact between the cover film and base layer. The base material is coated with the binder, subjected to heat and pressure to displace the binder around the embedded microsphere or corner cubes forming the bonded network. Retroreflective articles so constructed may be rigid and inflexible.
U.S. Pat. No. 4,576,850 to Martens, as well as U.S. Pat. Nos. 4,582,885 and 4,668,558 to Barber, disclose shaped plastic articles having replicated microstructure surfaces. These shaped plastic articles are made by crosslinked polymers with hard and soft segments having a microstructure-bearing surface that is replicated with a castable fluid and radiation hardened. Articles formed by this process exhibit, retro-reflective cube-corner sheeting, a Fresnel lens or a videodisc. All these formed articles are rigid and therefore unsuitable for use as ropes. Moreover, these articles also exhibit low tear strength.
U.S. Pat. No. 4,763,985 to Bingham discloses a launderable retroreflective appliqué that comprises a layer of transparent microspheres, a specular reflective layer optically connected to each microsphere, and a binder layer into which the microspheres are partially embedded. Resins disclosed as being suitable for use as binder layers include polyurethane, polyesters, polyvinyl acetate, polyvinyl chloride, acrylics, or combinations thereof. The specular reflective layers are composed of two succeeding layers of dielectric material. The layers have varying refractive indices and are composed of a variety of binary metal compounds including oxides, sulfides, and fluorides. This reflective appliqué is not a marine craft rope.
U.S. Pat. No. 4,815,818 to Thomas discloses three-dimensional flexible reflectors. The reflector is provided with an elastomeric resilient member having a plurality of embedded retro-reflective glass beads. A portion of the outer surface of the elastomeric material is removed to expose the glass beads. The exterior surface of the glass beads at the outer surface is exposed and is not a marine craft rope.
U.S. Pat. No. 4,950,525 to Bailey discloses elastomeric retroreflective sheeting. The elastomeric retroreflective sheeting has a monolayer of non-stretchable microspheres. These microspheres are embedded in a sheet with a spacing layer of transparent elestomeric material underlying the back surface of the microspheres. A cover layer of transparent elastomeric material covers the front surface of the microspheres. A specularly reflective layer is disposed on the back surface of the spacing layer. The cover layer comprises clear thermoplastic elastomeric aliphatic polyurethane. This retroreflective sheeting does not suggest a marine craft rope.
U.S. Pat. No. 4,957,335 to Kuney discloses microsphere-based retroreflective articles having high retroreflective brightness at narrow divergence or observation angles, i.e. up to 0.5 degrees. The article is made by selection of microspheres having defined combinations of average diameter and average refractive index. This patent teaches (column 4, lines 18-23) that variation in the size of the microspheres will increase the observation angle or divergence angle of the resultant retro-reflective article. The reflective spheres reflect only in a narrow range and the flat coating does not provide omnidirectional reflection.
U.S. Pat. No. 5,066,098 to Kult, et al. discloses a cellular, encapsulated-lens, high whiteness retroreflective sheeting having a flexible cover sheet. This cellular, encapsulated-lens retroreflective sheeting comprises a base sheet of a monolayer of retroreflective elements that is partially embedded in a binder layer, which typically is white. A cover sheet is disposed in spaced relation from the layer of retroreflective elements. A network of narrow intersecting bonds, or seal legs, that extend between the cover sheet and the base sheet with binder material are thermoformed at the point of contact between the base sheet and cover sheet. Such a rigid, reflective sheet is unsuitable for ropes, which require structures that can twist and flex. U.S. Pat. No. 5,117,304 to Huang, et al. discloses a retroreflective article. The retroreflective article has corner cubes and is flexible. It can be applied over irregular surfaces by using an optically clear, aliphatic polyurethane polymer. The aliphatic polymer is composed of a plurality of hard chain segments having the formula —C(O)N(H)—C6H10—N(H)C(O)—. The hard chains of cured polyurethane provide a hard, inflexible coating which cannot be applied over a flexible rope.
U.S. Pat. No. 5,200,262 to Li discloses a launderable retroreflective appliqué. The appliqué employs a reflector that comprises elemental aluminum or elemental silver on the backside of the microspheres. The appliqué comprises a monolayer of metal-coated microspheres partially embedded in and partially protruding from a binder layer. The binder layer comprises a flexible polymer having hydrogen functionalities and one or more isocyanate-functional silane coupling agents. The disclosed flexible polymers that possess hydrogen functionalities are crosslinked, flexible urethane-based polymers, such as isocyanate-cured polymers or one or two component polyurethanes and polyols. This reflective appliqué does not disclose or suggest the construction of a marine craft rope.
U.S. Pat. No. 5,283,101 to Li discloses a launderable retroreflective appliqué comprising a binder layer formed from an electron-beam curable polymer and typically one or more crosslinkers and silane coupling agents. Electron-beam curable polymers include chlorosulfonated polyethylenes, ethylene copolymers comprising at least about 70 weight percent of polyethylene, such as ethylene/vinyl acetate, ethylene/acrylate, and ethylene/acrylic acid, and poly(ethylene-co-propylene-co-diene) polymers. Glass microspheres are embedded in the cured binder layer, and a specular reflective metal layer is disposed on the embedded portions thereof. When the appliqué is inverted, light comes through the binder layer. This reflective appliqué provides no disclosure concerning a marine craft rope.
U.S. Pat. No. 5,777,790 to Nakajima discloses a microsphere-based retroreflective article. The retroreflective article comprises a monolayer of microspheres partially embedded in and protruding from a binder layer and specular reflector underlying the microspheres. The monolayer of microspheres comprises a mixture of a first class of microspheres having a first refractive index and a second class of microspheres having a second refractive index. The second refractive index is higher than the first refractive index. As a result, the sheeting exhibits superior observation angle angularity. This is a reflective coating with two layers having a different refractive index. There is no disclosure that this coating is applied to a rope; moreover the presence of two polymeric coatings may debond and degrade when bent or twisted.
U.S. Pat. No. 5,882,796 to Wilson, et al. discloses bonded structured retroreflective sheeting. The structured retroreflective sheeting includes an array of corner cube, structured retroreflective elements, a thermoplastic sealing film located proximate to the structured elements, and a bonding agent between the sealing film and the structured retroreflective elements. The bonding agent bonds the sealing film to the structured retroreflective film. This bonded structure is rigid and is unlikely to survive the flexing and twisting movements of a marine craft rope.
U.S. Pat. No. 5,926,314 to Smith, et al. discloses a retroreflective cube corner article having scalene base triangles. The cube corner retroreflective article exhibits a wide range of retroreflective entrance angularity in at least one plane, and preferably in two or more planes. The structured surface has an array of cube corner elements formed by three intersecting sets of substantially parallel grooves. Each cube corner element includes a base triangle bonded by one groove from each of the three intersecting groove sets, the base triangle being scalene. The corner cube reflector is rigid and cannot be used for producing reflective ropes.
U.S. Pat. No. 5,962,108 to Nestegard, et al. discloses a retroreflective polymer coated flexible fabric material and method of manufacture. The retroreflective polymeric coated flexible fabric material has a retroreflective layer and a polymeric compatibilizing layer welded to a polymeric coated outer surface of a flexible fabric material. The compatibilizing layer provides an intermediate layer between the retroreflective layer and the flexible fabric material, creating suitable bond strength between dissimilar polymers. Flexible fabric materials are polyester, nylon or cotton. The fabric is coated with highly plasticized polyvinyl chloride (PVC) or ethylene acrylic acid copolymer (EAA). These polymers are flexible, durable, and resistant to abrasion. The retroreflective prismatic elements layer includes: acrylic polymers, such as poly(methylmethacrylate); polycarbonates; cellulosics; polyesters such as poly(butyleneterephthalate); poly(ethyleneterephthalate); fluoropolymers; polyamides; polyetherketones; poly(etherimide); polyolefins; poly(styrene); poly(styrene) co-polymers; polysulfone; urethanes, including aliphatic and aromatic polyurethanes; and mixtures of the above polymers such as a poly(ester) and poly(carbonate) blend, and a fluoropolymer and acrylic polymer blend. The compatibilizing layer that is suitable for bonding between a retroreflective layer and a flexible fabric material that includes: polyurethane, ethylene methyl acrylate copolymer, ethylene N-butyl acrylate copolymer, ethylene ethyl acrylate copolymer, ethylene vinyl acetate copolymer, polymerically plasticized PVC, and polyurethane primed ethylene acrylic acid copolymer. Such a reflective fabric does not suggest the shape, construction or function of a marine craft rope.
U.S. Pat. No. 5,910,858 to Frey discloses retroreflective sheeting with a coated back surface. The retroreflective sheet has a plurality of indentations on the back surface to reflect the light, and a transparent front surface to encapsulate and protect the light reflecting indentations. This reflective sheet is rigid and is unsuitable for use as a marine craft rope.
U.S. Pat. No. 6,159,537 to Crandall discloses a method of making a retroreflective article that has a binder layer containing an epoxy resin and silicone crosslinked polymer. A pre-binder composition comprises about 5 to about 40 parts of an epoxy resin. About 60 to about 95 parts of an alkoxysilane terminated polymer is applied to a retroreflective layer and then cured to form a binder layer that is adhered to the retroreflective layer and an article of clothing. The binder composition does not cover the exterior surface of the reflective layer, and does not provide abrasion resistance needed for a marine craft rope.
U.S. Pat. No. 6,677,028 to Lasch, et al. discloses retroreflective articles having multilayer films and methods of manufacturing same. These retroreflective articles have multilayer films and are useful for commercial graphics and retroreflective products, such as roll-up signs for highway transportation safety. The articles comprise multilayer films having at least one layer of polyurethane and a core layer of a copolymer of alkylene and a bond layer of non-acidic, polar co-monomer including, ethylene copolymer, vinyl acetate, acrylate, EVA, acid-modified EVA, anhydride-modified EVA, acid-acrylate-modified EVA, anhydride-acrylate-modified EVA, EEA, EMA, AEA, EVACO, EBACO, and EnBA. The glass retroreflective beads comprise an air-exposed portion or have an overlay polyurethane or EAA cover film. When retroreflective glass beads are exposed to air, they are subject to wear; and therefore the multilayer retroreflective films articles may not be used on a marine craft rope.
U.S. published patent applications 20050157389 and 20050157390 to Shipman et al. discloses retroreflective elements and articles. The retroreflective elements and retroreflective articles are used as pavement markings and comprise retroreflective elements forming laminates. The retroreflective elements are not incorporated in a rope suited for marine craft use.
U.S. Pat. No. 4,167,156 to Kupperman, et al. discloses a reflective animal leather leash. The elongated leather animal leash includes a sewn a transparent polyvinyl chloride strip with a light reflective prism design on one surface. The light reflective prism is bonded by dielectric heat sealing or sonic welding to an opaque polyvinyl chloride strip sewn to the leather strip, resulting in a leash having a light reflective surface. Since the strip has a reflective surface on only one side of the leash, it does not reflect light in every direction. The flat leather leash is not easily twistable and is not readily bent without separating the transparent and opaque polyvinyl chloride layers. Therefore, this flat strip reflective configuration is unsuited for marine craft ropes.
U.S. Pat. Nos. 5,243,457 and 5,237,448 to Spencer disclose a material with enhanced visibility characteristics. This flexible visibility enhancing material combines the advantages of a light reflective component and a luminescent component. The material includes a first layer of prismatic light reflective plastic material having an underlying surface formed with a plurality of minute prism-like formations projecting therefrom at regular spaced intervals, and an overlying substantially smooth light transmissive surface. Bonded, i.e. by heat-sealing, to the first layer is a second layer of plastic luminescent material. The second layer is contiguously and integrally attached to the underlying surface of the prism-like formations and generally coextensive therewith. The visibility enhancing material simultaneously radiates luminescent light from the second layer through the underlying surface of prism-like formations and through the smooth light transmissive surface and reflects light from the prism-like formations through the smooth light transmissive surface. In one embodiment, the visibility enhancing material includes a flexible elongate member. In another embodiment, the second layer is replaced with a layer of luminescent material, which can be selectively energized to become luminous. This embodiment requires wires and illumination sources that can be easily integrated into a pet leash that can be twisted and flexed. Since the transparent reflective material is a molded plastic of prismatic construction it is rigid and is not flexible and does not form a leash that is capable of being twisted and bent, key functional requirements for a marine craft rope. Further any twisting and bending action separates the reflective element from the luminescent element.
U.S. Pat. No. 6,355,349 Chizmas discloses reflectively enhanced coated cable. This coated cable includes a structural core made of twined wire or other suitable material, and an outer thermoplastic layer surrounding the structural core, such outer core being transparent to light and a reflective layer that reflects the incident light imposed between the structural core and the outer layer. In a second embodiment, a reflective layer interposed between the structural core and the outer layer, the reflective layer being provided in the form of a wrapped tape disposed below the outer layer. The wrapped tape of reflective material is not braided and therefore cannot take the bending and twisting action of a marine craft rope.
U.S. Pat. No. 6,925,965 to Hurwitz discloses flexible omnidirectionally reflective pet leash having handle, central pet leash, and pet collar sections that reflect an incoming light beam back in the same direction as it was emanated. The reflected light beam provides accurate illumination of the pet owner's hand, pet leash and the location of the pet during dusk or nighttime hours. This flexible omnidirectionally reflective pet leash is created by surrounding a central braided rope of nylon or polyethylene fibers with a cylindrically braided reflective sleeve composed of narrow width reflective strips that comprise narrow woven, braided or knitted nylon or polypropylene strips thermally bonded to a flexible polymeric sheet with attached retroreflectors of the corner cube or microsphere configuration. This omnidirectionally reflective pet leash reflects light over a larger angle of acceptance, illuminating pet owner's hand, the leash, and the pet's collar, thereby providing an improved measure of safety for both the pet and the pet handler. This omnidirectional pet leash does not suggest a rope suitable for marine craft applications; and it does not contain a floatation core.
U.S. published patent applications 20060026933 and 20060026934 to Hurwitz disclose an omnidirectionally reflective horse halter. This flexible omnidirectionally reflective horse lead has a central portion, and mechanical attachment means to accommodate a bridal bit ring. The lead reflects an incoming light beam from a walker or horseback rider back in the direction from which it emanated, preventing dangerous encounters during dusk or nighttime hours. The omnidirectionally reflective elements may be incorporated in a horse harness, or in a halter suitable for horses roaming in a paddock or field. The reflective elements are created by surrounding a central braided rope of nylon or polyethylene fibers with a cylindrically braided reflective sleeve. The braided reflective sleeve is composed of narrow width reflective strips having a show surface with a flexible nylon retroreflective sheet sewn thereto. Reflectivity is achieved by thermally bonding corner cube or microsphere retroreflectors to a flexible polymeric sheet. Due to its braided construction, the reflective elements reflect light omnidirectionally over a large angle of acceptance, illuminating the horse harness or halter. An improved measure of safety is thereby provided for both the horse and the horseback rider. This omnidirectionally reflective horse halter is not a rope suitable for marine craft applications; and it does not contain a floatation core.
U.S. published patent application 20060027188 to Hurwitz discloses an abrasion resistant omnidirectionally reflective pet leash. This flexible abrasion resistant omnidirectionally reflective pet leash has handle, central pet leash, and pet collar sections that reflect an incoming light beam back in the same direction as it was emanated. The reflected light beam provides accurate illumination of the pet owner's hand, pet leash and the location of the pet during dusk or nighttime hours. This pet leash is created by surrounding a central braided rope of nylon or polyethylene fibers with a cylindrically braided reflective sleeve that is coated with an abrasion resistant transparent polymeric coating. The braided reflective sleeve is composed of narrow width reflective strips that comprise a woven or knitted narrow width strip and a flexible nylon retroreflective sheet sewn thereon. The flexible retroreflective sheet is formed by thermally bonding corner cube, microsphere retroreflectors, or wide-angle exposed retroreflective lenses to a flexible polymeric sheet. Due to its braided construction, the reflective pet leash reflects light omnidirectionally over a large angle of acceptance, illuminating the pet owner's hand, the leash itself, and the pet's collar, thereby providing an improved measure of safety for both the pet and the pet handler. This abrasion resistant omnidirectional pet leash does not suggest a rope suitable for marine craft applications; it does not contain a floatation core.
Notwithstanding the efforts of prior art workers to construct a marine craft rope, that there clearly exist a need in the art for a flexible, bendable rope that floats when thrown on water. Also needed in the art a rope that is omnidirectionally reflective, so that any light from a vessel is directly reflected back to the source regardless of its approaching direction, thereby providing enhanced visibility of the rope location with respect to a swimmer. Further needed are omnidirectional reflective rope markers for random floating objects such as buoys, fishing line markers, lobster pot markers and the like. The back reflection properties can be adversely affected by the retention of water on the surface of the reflective elements. Consequently, it would be advantageous for the omnidirectionally reflective rope to shed the water on areas thereof that are above the waterline as quickly as possible.